Nanostructured Metal Oxides and Sulfides for Lithium–Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries with high energy density and long cycle life are considered to be one of the most promising next-generation energy-storage systems beyond routine lithium-ion batteries. Various approaches have been proposed to break down technical barriers in Li-S battery systems. The use of nanostructured metal oxides and sulfides for high sulfur utilization and long life span of Li-S batteries is reviewed here. The relationships between the intrinsic properties of metal oxide/sulfide hosts and electrochemical performances of Li-S batteries are discussed. Nanostructured metal oxides/sulfides hosts used in solid sulfur cathodes, separators/interlayers, lithium-metal-anode protection, and lithium polysulfides batteries are discussed respectively. Prospects for the future developments of Li-S batteries with nanostructured metal oxides/sulfides are also discussed.

Recent development of metal compound applications in lithium–sulphur batteries

“…Polysulphides are likely to be chemically bonded at oxygen defect sites and surface defect of TiO 2 . 19 However, due to the insulation of TiO 2 , a conductive agent, such as CNT, graphene, etc., should be introduced rationally to generate a synergistic effect to produce high energy density and long life span Li-S batteries. Meanwhile Ti 4 O 7 , due to its low-coordinated Ti, is a promising polar host for the complex multielectron Li-S conversion reaction.…”

“…Ti x O y TiO 2 , due to its natural abundance, cost-effectiveness, and polar surface, has become the most widespread and popular metal oxide applied in Li-S batteries. 19 It was first used as an additive in the mesoporous carbonsulphur cathode of Li-S batteries by Nazar's group in 2012. 44 They investigate the role of surface adsorption versus pore absorption by using three kinds of TiO 2 with similar surface areas but different pore sizes (mesoporous a-TiO 2 with pore size of 5.2 nm, mesoporous b-TiO 2 with pore size of 9 nm, and nonporous c-TiO 2 , respectively) as the additives.…”

“…35,[40][41][42][43] What's more, compared to the carbon materials, the metal compounds' exposed surfaces and morphologies are easier to control by chemical and physical methods. 19 Thus a variety of nanostructured metal compounds were designed, such as hollow, 34 porous, 40 layered, 35 laminar-structured, 42 and so on, to effectively hold the polysulphides in Li-S batteries. However, compared to many reviews on the carbon and polymers materials used in Li-S batteries, the review on metal compounds for Li-S batteries are rare.…”

“…However, the conjugate nonpolar carbon planes have limited sites to strongly anchor polar molecules (e.g., lithium polysulphides and (di)sulphides). 19 To add anchoring sites and enhance anchoring ability of the carbon, tunable polar sites to chemically confine the polysulphides was introduced. Nanostructured carbon doped with heteroatoms (N, 20 S, 21 P, 22 B 23 ), and carbon modified with functional groups (amino-functionized, 24 carboxylfunctioned, 25 sulfonated, 26 fluorinated, 27 hydroxylated 28 ) as well as combined with conductive polymers, [29][30][31] have all been widely investigated for obtaining highperformance Li-S batteries.…”

State of the Art of Lithium-Ion Battery SOC Estimation for Electrical Vehicles

“…According to USABC, today's lithium-ion batteries cannot meet the standards of EVs. At present, lots of scholars, scientists, and engineers are focusing on new battery research such as Li-O 2 batteries [2,7], lithium-sulfur batteries [8][9][10][11][12][13][14], lithium metal batteries [15,16], all-solid-state lithium batteries [17], al-ion batteries [18], fuel cells [19][20][21][22], supercapacitors [23,24], and so on. Electric vehicles require a high power and…”